ABSTRACT Local protein synthesis within neuronal processes seems to be crucial for the rapid and dynamic remodeling of the proteome at synaptic compartments. Indeed, this capability enables neurons to swiftly adapt their synaptic functions in response to activity. In this review, we first explore the diverse mechanisms that allow the targeted transport of mRNAs into both dendrites and axons. Then, we report evidence that local mRNAs are actively recruited for protein synthesis during plasticity. Finally, we highlight how this molecular complexity contributes to the establishment and stabilization of memory traces, or engrams, within neural circuits. We propose that presynaptic protein synthesis is a pivotal factor driving the diversification of presynaptic terminals, a process we foresee as essential for the durable consolidation and specificity of engrams. image